A bio-nano-engineered platform fabricated from cerium oxide-carbon nanoparticles stabilized with chitosan for label-free sensing of a lung cancer biomarker.

Herein, we report a label-free cancer biosensor designed for carcinoembryonic antigen (CEA) detection using a nanohybrid comprising CeO nanoparticles, carbon nanoparticles (CNPs), and chitosan (Ch). CeO nanoparticles were prepared using a simple green synthesis process. A thin film of the CeO-CNPs-Ch nanohybrid was formed on indium tin oxide (ITO)-coated glass plates that endowed a high surface area, excellent stability, and good adsorption for the efficient loading of CEA antibodies. Quantitative and selective determination of CEA antigen was achieved by immobilizing monoclonal CEA antibodies (anti-CEA) on the CeO-CNPs-Ch/ITO platform. The electrochemical response of the anti-CEA/CeO-CNPs-Ch/ITO immunoelectrode was evaluated in a label-free immunoassay format using differential pulse voltammetry (DPV). The response studies of immunoelectrodes indicated wider linearity with respect to the CEA concentration in the range of 0.05-100 ng mL. The electrochemical cancer biosensor exhibited a higher sensitivity of 22.40 μA cm per decade change in concentration along with storage stability for up to 35 days. The limit of detection (LOD) was 0.037 ng mL. Furthermore, this cancer biosensor exhibited good specificity and reproducibility. Thus, the proposed CeO-CNPs-Ch nanocomposite-based platform provides an efficient method for the analysis of other antigen-antibody interactions and biomolecule detection. The efficacy of the anti-CEA/CeO-CNPs-Ch/ITO immunoelectrode was further examined by measuring CEA levels in human serum.